JP2000155555A - Drive methods of electron emission element and electron source and image forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain stable electron emission characteristics for a long term by preventing an electron emission element from deteriorating in electron emission characteristics. SOLUTION: When a voltage Vf is applied on an electron emission element, a current If1 of the element flowing through the electron emission element is measured (S2), and when the voltage Vf is applied on the electron emission element after the measurement process, a current If2 of the element flowing through the electron emission element is measured. Here, when the current If2 of the element is larger than the current If1, a larger voltage V2 than the voltage V1 is applied (S5) on the electron emission element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for driving an electron-emitting device, a method for driving an electron source having a plurality of the electron-emitting devices, and a method for driving an image forming apparatus using the electron source.

[0002]

2. Description of the Related Art Conventionally, two types of electron emitting devices, a hot cathode device and a cold cathode device, are known. Among them, in the cold cathode device, for example, a surface conduction electron-emitting device, a field emission electron-emitting device (hereinafter, referred to as FE type), a metal / insulating layer / metal-type electron emission device (hereinafter, referred to as MIM type), It has been known.

[0003] As a surface conduction type emission element, for example, M.
I. Elinson, Radio Eng. Electron Phys., 10, 1290, (1965)
Etc. are known.

The surface conduction electron-emitting device utilizes a phenomenon in which an electron is emitted when a current flows in a small-area thin film formed on a substrate in parallel with the film surface. As this surface conduction type emission element, there is an element using a SnO2 thin film by Elinson or the like. In addition, those using carbon thin films [Hisashi Araki et al .: Vacuum, Vol. 26,
No. 1, 22 (1983)].

[0005] A surface conduction electron-emitting device coated with a carbon film is disclosed in Japanese Patent No. 02861515.

[0006] The above-mentioned elements have the advantage that a large number of elements can be arranged and formed over a large area since they have a simple structure and are easy to manufacture.

In recent years, flat panel display devices using liquid crystal have become widespread in place of CRTs. However, since the LCD is not a self-luminous type, there is a problem that a backlight must be provided. Therefore, development of a self-luminous display device has been desired. Such a self-luminous display device is an image display device that combines an electron source having a large number of surface conduction emission elements and a phosphor that emits visible light by electrons emitted from the electron source. Forming apparatus.

[0008]

FIGS. 20 (a) and 20 (b) show an example of the structure of an element of the type coated with a carbon film.

In FIG. 1, 1 is a substrate, 2 and 3 are electrodes,
4 is a conductive film, 6 is a first gap, 7 is a second gap, 10
Is a carbon film.

FIGS. 21 (a) to 21 (d) show an example of a method of manufacturing an element of a type coated with a carbon film 10. FIG.

First, the electrodes 2 and 3 are arranged on the substrate 1 (FIG. 21A). Then, a conductive film 4 connecting the electrodes 2 and 3 is arranged (FIG. 21B). Next, the conductive film 4
The first gap 6 is formed in a part of the conductive film 4 by passing an electric current through the electrode (referred to as a forming step) (FIG. 21).
(C)). Next, for example, a voltage is applied between the electrodes 2 and 3 in an atmosphere containing an organic substance to form the carbon film 10 (FIG. 21D). The second gap 7 is formed simultaneously with the formation of the carbon film 10. By this step, a second gap 7 narrower than the first gap 6 can be formed. The vicinity of the second gap 7 is referred to as an electron emitting section 5. Further, the carbon film 10 contains carbon and / or a carbon compound.

The step of forming the gap 7 narrower than the first gap 6 formed by the forming step and improving the electron emission characteristics is called an activation step. Note that the activation step is not necessarily required as long as sufficient electron emission characteristics can be obtained by the gap 6 formed by the forming step. However, it is preferable to perform the above activation step in view of the stability of the electron emission characteristics and the range of selectivity of the material used for the conductive film.

It is preferable that the element having the gap formed by each of the above steps is further subjected to a step called a stabilization step. Specifically, the stabilizing step is to heat the element and the container in which the element is disposed, to thereby reduce the organic substance existing in the atmosphere surrounding the element to a state in which no new carbon or carbon compound is deposited. This is the step of removing / evacuating.

The electron-emitting device formed by the above steps is driven as follows.

That is, the device voltage (Vf) is applied between the electrodes 2 and 3 in the reduced pressure atmosphere formed in the stabilization step, and at the same time, the anode voltage (Va) is applied to the anode electrode disposed above the device. Apply. The current flowing between the electrodes 2 and 3 when the voltage Vf is applied between the electrodes 2 and 3 is called an element current If, and the current emitted from the element and flowing into the anode electrode at this time is called an emission current Ie. Call.

The device characteristics (the relationship between the emission current Ie and the device current If with respect to Vf) of the device described above are approximately as shown in FIG.
Note that Vth in FIG. 6 is a device voltage at which the emission current Ie starts to be observed.

Japanese Patent Application Laid-Open No. Hei 8-96700 discloses that after the above-mentioned stabilization step, the device has a maximum voltage value (Vma) of the device voltage Vf applied during the manufacturing process and during driving.
It is disclosed that the emission current Ie and the device current If, which depend on x), continue to maintain characteristics (memory characteristics) that are almost uniquely determined.

The above-mentioned publication further discloses that the device voltage applied to the device after the stabilization step at a certain time exceeds the maximum value (Vmax) of the device voltage Vf applied before that. In this case, it is disclosed that the relationship between the emission current Ie and the device current If with respect to the device voltage Vf and the device characteristics change. Specifically, the maximum element voltage V
It discloses that a device characteristic characterized by max changes to a device characteristic characterized by a voltage exceeding Vmax (Vmax dependency).

The above-mentioned publication discloses that this characteristic (memory property, Vmax dependence) is used to correct the characteristic variation of the element after the stabilization step.

However, it is difficult to maintain the atmosphere formed in the stabilizing step and to form an atmosphere desired in the stabilizing step. Therefore, when the removal of the organic substance in the stabilization step is insufficient, the following problems may occur.

Problem: If the device has been driven for a long time after the stabilization step, the device characteristics which should continue to be characterized by the maximum voltage value (Vmax) may fluctuate. That is, the aforementioned memory property is lost. The element current I
f, the emission current Ie becomes unstable. Such a phenomenon occurs when new carbon or carbon compound is added to the gap 6 of the electron-emitting device.
It is presumed that a structural change in the vicinity of the gap has occurred, such as formation near the gap 7.

The above specific phenomena include, for example,
While the device is driven at a voltage value V1 lower than the above-described maximum voltage value (Vmax), the characteristics characterized by the voltage value V1 (the characteristics of the device current with respect to the device voltage or the characteristics of the emission current with respect to the device voltage) ) Gradually. More specifically, the respective curves of the device current If and the emission current Ie with respect to the device voltage Vf shown in FIG. 6 move to the left. As a result, it is considered that the element current If and the emission current Ie increase even when driving is performed at the same element voltage value Vf.

This phenomenon becomes more problematic in the case of an electron source that connects a plurality of elements to a common wiring. That is,
A wiring to which a plurality of elements are connected has a certain resistance value, and each element has a characteristic that an element current If flows. For this reason, when one of the elements A among the elements wired in common causes the above-described characteristic fluctuation (particularly, an increase in the element current If), the effective element voltage applied to the adjacent element B decreases. . Therefore, in consideration of the above phenomenon, if the effective element voltage Vf applied to the element B decreases, the characteristic fluctuation of the element B becomes larger than the characteristic fluctuation of the element A. When the elements are connected in common as described above, the characteristic variation of each element progresses in a chain.

Problem: On the other hand, the maximum voltage value (Vmax)
When the element is continuously driven in the above, the element current If and the emission current Ie may be significantly deteriorated. One of the reasons for such a phenomenon is a structural change in the vicinity of the gap 6 or the gap 7 due to an organic substance gas remaining without being completely removed in the stabilization step or heat related to the driving. It is presumed that it is happening.

Means for improving fluctuations in element characteristics which are considered to be caused by the atmosphere surrounding the element are described in, for example, JP-A-9-50256, JP-A-6-28981, JP-A-6-289814, and 2598
No. 301, JP-A-9-199006 and the like.

From the above-mentioned phenomenon, while driving at the voltage value V1 at regular intervals at predetermined intervals so as to maintain the element characteristics characterized by the maximum voltage value (Vmax). It is also conceivable to apply the maximum voltage value (Vmax).

However, in this case, the maximum voltage value (Vmax) may be applied unnecessarily. For example,
In the case of a flat panel display using an electron source in which a large number of the elements are arranged, a displayed image always changes, so that driving conditions and frequencies are different for each element. For this reason, when the maximum voltage value (Vmax) is periodically applied to all the elements at a predetermined interval, if the characteristics do not change or the degree of the change is small, Also, the maximum voltage value (Vmax) is applied.

In such a case, as in the case described above, the device current If and the emission current Ie may be significantly deteriorated during long-time driving.

By applying the maximum voltage value (Vmax), an increase in the device current and emission current for a predetermined drive voltage value (Vf) can be suppressed. However, on the other hand, for an element whose characteristics are not changed or whose degree of change is small, the deterioration of the element characteristics is dominant because the execution time in which the unnecessary maximum voltage value (Vmax) is applied is long. There was a case.

The present invention has been made in view of the above-mentioned problems, and a method of driving an electron-emitting device which suppresses fluctuation and deterioration of electron-emitting characteristics, and a method of driving an electron source using the electron-emitting device. It is an object to provide a method and a driving method of an image forming apparatus using the electron source.

[0031]

In order to achieve the above object, a method for driving an electron source according to the present invention comprises the following steps.

When a voltage V1 is applied to the electron-emitting device,
An emission current Ie1 emitted from the electron-emitting device, and / or a first measurement step of measuring an element current If1 flowing through the electron-emitting device, and after the first measurement step,
A second measuring step of measuring an emission current Ie2 emitted from the electron-emitting device and / or an element current If2 flowing through the electron-emitting device when a voltage V1 is applied to the electron-emitting device; and Is larger than Ie1, and / or when the device current If2 is larger than If1, a voltage V2 larger than the voltage V1 is applied to the electron-emitting device.
And applying a voltage.

Further, as another mode of the driving method of the electron-emitting device according to the present invention, when a pulse-like voltage is applied to the electron-emitting device, an emission current I emitted from the electron-emitting device is obtained.
e1, and a first measurement step of measuring the device current If1 flowing through the electron-emitting device, and after the first measurement step, the same waveform as the pulsed voltage was applied to the electron-emitting device. At this time, a second measurement step of measuring the emission current Ie2 emitted from the electron-emitting device, and / or the device current If2 flowing through the electron-emitting device, and when the emission current Ie2 is larger than Ie1, and / or When the device current If2 is larger than If1, a pulse having a power larger than the power of the pulse applied in the first measurement step (a value obtained by integrating a voltage value with respect to time) is applied to the electron-emitting device. Voltage applying step of applying a voltage.

Further, the present invention is characterized in that after performing the voltage applying step, the first measuring step, the second measuring step, and the voltage applying step are further repeated.

The present invention is also characterized in that the voltage V2 is equal to or less than a maximum voltage value Vmax applied to the electron-emitting device before the first measuring step.

The present invention is also characterized in that the voltage applied to the electron-emitting device is a pulse voltage.

Further, the present invention is characterized in that the power of the pulse applied in the voltage applying step is not more than the maximum power applied to the electron-emitting device before the first measuring step. And

Further, the present invention relates to a method for driving an electron source having a plurality of arrayed electron-emitting devices, wherein the electron-emitting devices are driven using the method for driving the electron-emitting devices.

Further, the present invention is a method for driving an image forming apparatus having an electron source and an image forming member, wherein the electron source is driven by the method for driving the electron source.

According to the driving method of the present invention described above,
It is possible to provide an electron-emitting device, an electron source, and an image forming apparatus in which fluctuations in electron emission characteristics are small and deterioration is suppressed even when the device is driven for a long time.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

The basic structure of the electron-emitting device applicable to the present invention is roughly classified into two types: a planar type and a vertical type. First, the planar type will be described.

FIGS. 1A and 1B are schematic views showing the structure of a flat type electron-emitting device applicable to the present invention. FIG. 1A is a plan view and FIG. 1B is a cross-sectional view.

In FIG. 1, 1 is a substrate, 2 and 3 are electrodes,
Reference numeral 4 denotes a conductive film, and reference numeral 5 denotes an electron-emitting portion. As the substrate 1, quartz glass, glass with a reduced content of impurities such as Na, blue plate glass, a glass substrate in which a blue plate glass is laminated with SiO2 formed by a sputtering method or the like, ceramics such as alumina, a Si substrate and the like can be used. it can.

As the material of the electrodes 2 and 3 facing each other, a general conductor material can be used. This is, for example, Ni, Cr, Au, Mo, W, Pt, Ti, Al,
Metals or alloys such as Cu and Pd and Pd, Ag, Au, R
It can be appropriately selected from a printed conductor made of a metal such as uO2, Pd-Ag or the like and a metal oxide and glass, a transparent conductor such as In2O3-SnO2, or a semiconductor conductor material such as polysilicon.

The shape such as the interval L between the electrodes 2 and 3, the electrode width W1, the width W2 of the conductive film 4, and the like are appropriately designed in consideration of the applied form and the like. The distance L between the electrodes 2 and 3 can be preferably in the range of several hundred nm to several hundred μm, and more preferably in the range of several μm to several tens μm. The length W1 of the electrodes 2 and 3 can be in the range of several μm to several hundred μm in consideration of the resistance values and the electron emission characteristics of these electrodes 2 and 3. The thickness d of the electrodes 2 and 3 can be in the range of several tens nm to several μm. FIG.
In addition to the configuration shown in FIG. 5, a configuration in which a conductive film 4 and opposing electrodes 2 and 3 are laminated on a substrate 1 in this order can also be adopted.

The thickness of the conductive film 4 is appropriately set in consideration of the step coverage of the electrodes 2 and 3, the resistance between the electrodes 2 and 3, the forming conditions described later, and the like. It is preferably in the range of several times 0.1 nm to several hundred nm, more preferably in the range of 1 nm to 50 nm. The resistance value Rs is 10 to the power of 10
7 [Ω / □]. Note that this resistance value Rs is
The resistance R of a thin film having a thickness t, a width w, and a length L is represented by R =
It is a resistance value when Rs (L / w).

In the specification of the present application, the forming process will be described taking the energizing process as an example. However, the forming process of the present embodiment is not limited to this, and the gap 6 is formed in the conductive film 4. It includes processing.

The material constituting the conductive film 4 is Pd, P
t, Ru, Ag, Au, Ti, In, Cu, Cr, F
metals such as e, Zn, Sn, Ta, W, Pd, PdO, S
It is appropriately selected from oxides such as nO2, In2O3, PbO, and Sb2O3.

It is preferable to use a fine particle film made of fine particles for the conductive film 4 in order to obtain good electron emission characteristics.

The fine particle film described here is a film in which a plurality of fine particles are aggregated, and has a fine structure in a state where the fine particles are individually dispersed and arranged, or in a state where the fine particles are adjacent to each other or overlapped (some). (Including the case where the fine particles aggregate to form an island-like structure as a whole). The particle size of the fine particles ranges from several times 0.1 nm to several hundred nm,
Preferably, it is in the range of 1 nm to 20 nm.

In the specification of the present application, the term "fine particles" is frequently used, and its meaning will be described below. Small particles are called "fine particles" and smaller ones are called "ultra fine particles". It is widely practiced to call a “cluster” a particle that is smaller than “ultra-fine particles” and has a few hundred atoms or less.

However, each boundary is not strict, and changes depending on what kind of property is focused on. Further, “fine particles” and “ultrafine particles” may be collectively referred to as “fine particles”, and the description in this specification is in line with this.

The following is described in “Experimental Physics Course 14 Surface / Particles” (edited by Yoshio Kinoshita, published by Kyoritsu Shuppan, September 1, 1986).

"In the present description, the fine particles have a diameter of about 2 to 3 μm to about 10 nm, and especially the ultrafine particles have a particle diameter of about 10 nm to 2 to 3 nm.
It means up to about nm. It is not exactly strict because both are collectively written as fine particles, but it is a rough guide. When the number of atoms constituting a particle is two to several tens to several hundreds, it is called a cluster. "
(Page 195, lines 22-26).

In addition, the definition of “ultrafine particles” in the “Hayashi / Ultrafine Particle Project” of the New Technology Development Corporation has a lower limit of the particle size, as follows.

In the “Ultra Fine Particle Project” of the Creative Science and Technology Promotion System (1981 to 1986), a particle having a size (diameter) of about 1 to 100 nm is called “ultra fine particle”. Thus, one ultrafine particle is an aggregate of about 100 to 108 atoms. Ultrafine particles are large to giant particles on an atomic scale. " Science and Technology-Hayashi Tax, Ryoji Ueda, Akira Tazaki, Mita Publishing 198
8th year, page 2, lines 1 to 4) "A particle smaller than an ultrafine particle, that is, a single particle composed of several to several hundred atoms, is usually called a cluster."
Lines 2-13).

[0058] Based on the general notation as described above,
In the specification of the present application, the term “fine particles” refers to an aggregate of a large number of atoms and molecules, and the lower limit of the particle size is from several times 0.1 nm to about 1 nm, and the upper limit is about several μm.

Next, in the case of an element which does not require the above-mentioned activation step, the electron emitting portion 5 indicates the vicinity of the first gap 6 formed in a part of the conductive film 4 (FIG. 21 (c)). )). In the case of an element requiring the above-described activation step, the electron-emitting portion 5 indicates the vicinity of the second gap 7 smaller than the first gap 6 formed in the conductive film 4 (FIG. 21). (D)).

The elements to which the driving method according to the present embodiment can be preferably applied include a pair of conductive films 4 opposed to each other with a gap 6 as shown in FIGS. This is a type of element in which electrons are emitted from the vicinity of the gap 6 or 7 by applying a potential to a pair of conductive films (carbon films 10) opposed to each other with the gap 7 therebetween. In other words, this is a driving method preferably applied when driving a device of a type in which a voltage is applied to a pair of conductive films facing each other with a minute gap on the order of nanometers (nm) under reduced pressure.

In FIGS. 1 and 20, the gaps 7, 6 and the electron-emitting portion 5 are shown with a uniform width and in a straight line, but this is shown schematically. The actual gap shape may meander, or the width (interval) of the gap 7 (and / or the gap 6) may vary depending on the location. Further, a part of the gap 7 (and / or the gap 6) is connected (the conductive film 4 and / or the carbon film 1).
0 may be continuous). However, since the connected area is very small, the area including the connected area is referred to as a gap (7, 6).

The first gap 6 depends on the thickness, film quality, and material of the conductive film 4 and a technique such as energization forming which will be described later.

The second gap 7 depends on the activation condition described later.

In some cases, conductive fine particles having a particle size in the range of several times 0.1 nm to several tens nm are present inside the electron emitting portion 5. The conductive fine particles contain some or all of the elements of the material constituting the conductive film 4.

Next, a vertical type surface conduction electron-emitting device will be described. FIG. 2 is a schematic diagram illustrating an example of a vertical electron-emitting device. In FIG. 2, the same parts as those shown in FIG. 1 are denoted by the same reference numerals. Further, the electron-emitting portion 5 is the same as that of the above-mentioned flat type, so that the description is omitted.

The substrate 1, the electrodes 2 and 3, the conductive film 4, and the electron-emitting portion 5 can be made of the same material as in the case of the above-mentioned flat type electron-emitting device. Step forming member 21
Is S formed by vacuum deposition, printing, sputtering, etc.
It can be made of an insulating material such as iO2. The film thickness of the step forming member 21 corresponds to the electrode interval L of the above-mentioned flat type electron-emitting device, and can be in the range of several tens nm to several hundreds μm. This film thickness is set in consideration of the manufacturing method of the step forming portion 21 and the voltage applied between the electrodes 2 and 3, and is preferably in the range of several tens nm to several tens μm.

The conductive film 4 is laminated on the electrodes 2 and 3 after the electrodes 2 and 3 and the step forming member 21 are formed. In FIG. 2, the electron emitting portion 5 is provided with the step forming member 2.
Although it is formed on one side surface, the shape and position are not limited to these depending on the forming conditions, forming conditions and the like.

There are various methods for manufacturing the above-described electron-emitting device. One example is schematically shown in FIGS. 3 (a) to 3 (c) and FIGS. 21 (a) to 21 (d). Hereinafter, an example of a method of manufacturing a flat-type electron-emitting device will be described with reference to FIGS. 1 and 3, FIG. 20, and FIG. In FIG. 3, the same parts as those shown in FIG. 1 are denoted by the same reference numerals.

(1) The substrate 1 is sufficiently washed with a detergent, pure water, an organic solvent, or the like, and the electrode material is deposited by a vacuum deposition method, a sputtering method, or the like. The electrodes 2 and 3 are formed thereon (FIG. 3
(A), FIG. 21 (a)).

(2) An organic metal solution is applied to the substrate 1 provided with the electrodes 2 and 3 to form an organic metal thin film. As the organic metal solution, a solution of an organic metal compound containing a metal of the material of the conductive film 4 as a main element can be used.
This organic metal thin film is heated and baked, and is patterned by lift-off, etching, or the like to form a conductive film 4 (FIGS. 3B and 21B). Here, the method of applying the organometallic solution has been described, but the method of forming the conductive film 4 is not limited to this, and a vacuum deposition method, a sputtering method,
A chemical vapor deposition method, a dispersion coating method, a dipping method, a spinner method, or the like can also be used.

(3) Subsequently, a forming step is performed. As an example of a method of the forming step, a method by an energization process will be described. When a current is applied to the conductive film 4 using a power supply (not shown), the electron-emitting portion 5 is formed in a part of the conductive film 4 (FIGS. 3C and 21C). The first gap 6 formed in a part of the conductive film 4 by this forming step and the vicinity thereof constitute the electron emission section 5.

In the case of an element requiring the above-described activation step, the electron-emitting portion 5 is formed through the following activation step.

FIG. 4 shows an example of the voltage waveform of the energization forming.
(A) and (b).

The voltage waveform applied in this forming step is preferably a pulse waveform. The method shown in FIG. 4A in which a pulse having a pulse peak value of a constant voltage is applied continuously is applied to the method, and a voltage pulse is applied while increasing the pulse peak value as shown in FIG. 4B. There is a way to do it.

In FIGS. 4A and 4B, T1 and T2 indicate the pulse width and pulse interval of the voltage waveform, respectively. Usually, T1 is 1 μsec to 10 msec, and T2 is 10 μsec.
It is set in the range of seconds to 100 ms. The peak value of this rectangular wave (peak voltage at the time of energization forming) is appropriately selected according to the form of the electron-emitting device. Under such conditions, for example, a voltage is applied for several seconds to several tens minutes. Note that the pulse waveform is not limited to a rectangular wave, and a desired waveform can be adopted.

Further, T1 and T2 in FIG.
This can be the same as that shown in FIG. In FIG. 4B, the peak value of the rectangular wave (peak voltage during energization forming) is, for example, 0.1 [V / step].
Can be increased by degrees.

The end of the energization forming process can be detected by applying a voltage that does not locally destroy or deform the conductive film 4 during the pulse interval T2 and measuring the element current flowing through the element at that time. it can. For example, a device current flowing when a voltage of about 0.1 V is applied is measured, and a resistance value at that time is obtained. When the resistance value indicates a resistance of 1 MΩ or more, the energization forming is terminated.

(4) Subsequently, an activation step is performed on the element requiring the above-described activation step. In this step, application of a pulse voltage is repeated, for example, in an atmosphere containing an organic substance gas, similarly to the above-described forming step.
It is desirable that the voltage value applied to the element in the activation step is higher than the voltage value applied in the above-described forming.

According to this step, the second gap 7 is formed at the same time as the carbon film 10 is formed inside the first gap 6 and on the conductive film 4. Through this step, the electron-emitting portion 5 is formed (FIG. 21D). Note that FIG.
In order to form the carbon film 10 substantially symmetrically with the gap 7 interposed therebetween as shown in FIG.
It is necessary to use bipolar pulses as shown in (a) and (b).

The atmosphere containing the organic substance gas is as follows:
For example, when the inside of the vacuum vessel is evacuated using an oil diffusion pump, a rotary pump, or the like, it can be formed using an organic gas remaining in the atmosphere. Alternatively, it can be obtained by introducing a gas of an appropriate organic substance into a vacuum once sufficiently evacuated by an ion pump or the like. At this time, the preferable gas pressure of the organic substance is different depending on the above-described application form, the shape of the vacuum vessel, the type of the organic substance,
It is set appropriately according to the case.

Suitable organic substances include alkanes,
Alkenes, aliphatic hydrocarbons of alkynes, aromatic hydrocarbons, alcohols, aldehydes, ketones, amines, phenols, carboxyls, organic acids such as sulfonic acids and the like, and specifically, Saturated hydrocarbons represented by CnH2n + 2 such as methane, ethane, and propane; unsaturated hydrocarbons represented by a composition formula such as CnH2n such as ethylene and propylene; benzene, toluene, methanol, ethanol, formaldehyde, acetaldehyde, acetone, and methyl ethyl ketone , Methylamine, ethylamine, phenol, formic acid, acetic acid, procionic acid and the like, or mixtures thereof. By this treatment, a carbon film 10 (carbon or carbon compound) is formed in the vicinity of the first gap 6 from the organic substance existing in the gas atmosphere, and the characteristics of the device current If and the emission current Ie with respect to a predetermined driving voltage are reduced. It will change significantly. The end of this activation step is determined by
The measurement is appropriately performed while measuring the element current If and the emission current Ie.
The applied pulse width T1, pulse interval T2, pulse crest value and the like are set as appropriate.

The carbon (carbon and / or carbon compound) formed in the activation step is, for example, graphite (HOPG including so-called HOPG, PG and GC).
Indicates a crystal structure of almost perfect graphite, PG indicates a crystal having a crystal grain of about 20 nm and the crystal structure is slightly disordered, and GC indicates a crystal having a crystal grain of about 2 nm and disorder of the crystal structure is further increased.) Carbon (refers to amorphous carbon and a mixture of amorphous carbon and the microcrystals of graphite). The thickness of the carbon film 10 is preferably in the range of 1 nm to 50 nm, and more preferably in the range of 1 nm to 30 nm.

(5) It is preferable that the electron-emitting device obtained through the above steps is further subjected to a stabilization step thereafter. This stabilization step is a step of exhausting the organic substance in the vacuum vessel. The vacuum exhaust device that exhausts the vacuum vessel
It is preferable to use oil-free oil so that the oil generated from the exhaust device does not significantly affect the characteristics of the element. Specifically, a vacuum exhaust device such as a sorption pump and an ion pump can be used.

In the above-described activation step, when an oil diffusion pump or a rotary pump is used as an exhaust device and an organic gas derived from an oil component generated therefrom is used, it is necessary to keep the partial pressure of this component as low as possible. . Further, when evacuating the inside of the vacuum vessel, it is preferable to heat the entire vacuum vessel so that the organic substance molecules adsorbed on the inner wall of the vacuum vessel and the electron-emitting device are easily evacuated. The heating condition at this time is 80
To 250 ° C., more preferably 150 ° C. or higher, it is desirable to perform the treatment for as long as possible, but it is not particularly limited to this condition, and the size and shape of the vacuum vessel,
This is performed under conditions appropriately selected according to various conditions such as the configuration of the electron-emitting device. The pressure in the vacuum vessel must be as low as possible, and is preferably 1 × 10 −5 [Pa] or less, more preferably 1.3 × 10 −6 [Pa] or less.

(6) After performing the stabilization step in this manner, it is preferable that the atmosphere at the time of actual driving maintain the atmosphere at the end of the stabilization processing.

The basic characteristics of the electron-emitting device obtained through the above-described steps and applicable to the present embodiment will be described with reference to FIGS.

FIG. 5 is a block diagram showing an example of a vacuum processing apparatus having a function for practicing the method for driving an electron-emitting device according to the present embodiment and a function for measuring and evaluating device characteristics. In addition, parts common to the above-described drawings are denoted by the same reference numerals, and description thereof will be omitted.

In FIG. 5, reference numeral 50 denotes an ammeter;
It is used to measure the device current If flowing through the conductive film 4 between the three. Reference numeral 51 denotes a power supply, and electrodes 2 and 3 of the electron-emitting device.
A voltage is applied between them. An ammeter 52 is used to measure the emission current Ie emitted from the electron emission portion 5 of the device. Reference numeral 53 denotes a high-voltage power supply for applying a voltage to the anode electrode 54; 54, an anode electrode for capturing electrons emitted from the electron emission portion 5 of the device; 55, a vacuum device; and 56, an exhaust pump. Reference numeral 57 denotes an element current monitoring controller which operates to give an instruction to the power supply 51 so that the voltage output from the power supply 51 becomes the voltage V2 when the ammeter 50 detects an increase in the element current If. Reference numeral 58 denotes an emission current monitoring controller.
When the power supply 5 detects an increase in
Give instructions to 1. Here, as an example, the voltage Va of the anode electrode 54 is in the range of 1 kV to 10 kV, and the distance H between the anode electrode 54 and the electron-emitting device is 2 mm to 8 mm.
Measurements can be made in the range of mm.

The vacuum vessel 55 is provided with equipment necessary for measurement in a vacuum atmosphere, such as a vacuum gauge (not shown), so that measurement and evaluation can be performed in a desired vacuum atmosphere. . The exhaust pump 56 is composed of a normal high vacuum device system including a turbo pump and a rotary pump, and an ultra-high vacuum device system further including an ion pump and the like. The entire vacuum processing apparatus provided with the electron source substrate shown here can be heated by a heater (not shown). Therefore, by using this vacuum processing apparatus, the steps after the energization forming described above can also be performed.

FIG. 6 shows emission current Ie, device current If and device voltage Vf measured using the vacuum processing apparatus shown in FIG.
FIG. 4 is a graph diagram schematically showing the relationship of FIG. In FIG. 6, since the emission current Ie is significantly smaller than the element current If, it is shown in arbitrary units. In FIG. 6, both the vertical and horizontal axes are shown on a linear scale.

In FIG. 6, an example in which the device current If monotonically increases with respect to the device voltage Vf (MI characteristic) is shown by a solid line. Conversely, the element current If may exhibit a voltage-controlled negative resistance characteristic (VCNR characteristic) with respect to the element voltage Vf (not shown), but the element characteristic in which the driving method of the present embodiment can be adopted. Is a case where the above-mentioned element current If shows MI characteristics in which the element current monotonically increases with respect to the element voltage Vf.

Here, the electron-emitting device according to the present embodiment has the following three characteristic properties regarding the emission current Ie.

(I) When an element voltage higher than a certain voltage (threshold voltage (Vth in FIG. 6)) is applied, the emission current Ie sharply increases. On the other hand, when the element voltage is lower than the threshold voltage Vth, the emission current Ie is hardly detected. That is, it is a non-linear element having a clear threshold voltage Vth with respect to the emission current Ie.

(Ii) Since the emission current Ie monotonically increases in accordance with the device voltage Vf, the emission current Ie can be controlled by the device voltage Vf.

(Iii) The emission charge captured by the anode electrode 54 depends on the time during which the device voltage Vf is applied. That is, the amount of charge captured by the anode electrode 54 can be controlled by the time (pulse width) for applying the device voltage Vf.

As understood from the above description, the electron-emitting device according to the present embodiment can easily control the electron-emitting characteristics according to the input signal. Utilizing this property, it can be applied to various fields such as an electron source having a plurality of electron-emitting devices and an image forming apparatus.

In the stabilization step after the above-described forming step and / or activation step, the exhaust pump 56
If the exhaust air is insufficient, or if the baking by the heater (not shown) is insufficient, the removal of the organic substance is incomplete. As a result, as described above, the aforementioned M
Although exhibiting the I characteristic, the electron emission characteristics of the electron-emitting device change during long-time driving.

Thus, the voltage-device current characterized by the maximum voltage value (Vmax) applied to the device,
Alternatively, the memory property in which the voltage-emission current characteristics are stored is lost. Further, an element current If with respect to a predetermined element voltage Vf,
The characteristics of the emission current Ie become unstable.

In the case of an element that has been subjected to the activation step, the maximum voltage value (Vmax) can be regarded as the maximum voltage value applied to the element in the activation step.

Further, the above-mentioned “lost memory property” means that
For example, after the stabilization step, the maximum voltage value (V
When the device is driven at a voltage Vf lower than (max), the characteristic shifts to a voltage-device current (or voltage-emission current) characteristic characterized by the voltage Vf.
f, indicates that a fluctuation occurs such that the emission current Ie increases.

Therefore, the driving method according to the present embodiment is as follows.
Even in such a situation, it is possible to effectively suppress a temporal characteristic change due to an increase in the element current If and the emission current Ie.

Note that “driving” and “driving method” according to the present embodiment mean a step of applying a voltage to the electron-emitting device after manufacturing the device. For example, in the element that performs the activation step, the forming step described above;
When the activation step and the stabilization step are completed, the manufacturing process of the electron-emitting device is completed.

Hereinafter, an example of the driving method according to the present embodiment will be described.

For example, after the stabilization step, several measurement voltages V1 having different voltage values are applied to the device. Then, an initial element current If1 measured for the measured voltage V1 is measured and stored in a memory or the like (first measurement step). The measured voltage V1 is equal to the maximum voltage Vmax.
The following voltage is preferable, and the voltage V used during driving is preferably
f.

In the case of a driving method in which the amount of electrons emitted from the electron-emitting device is controlled by the pulse width of the pulse voltage applied to the device, the driving voltage Vf is constant. for that reason,
It is preferable that the measurement voltage V1 is set to be the same as the drive voltage value Vf, and the initial element current If1 is measured and stored.

On the other hand, the amount of electrons emitted from the electron-emitting device is
In the case of a driving method in which the driving is controlled by the pulse peak value of the pulse voltage applied to the element, the driving voltage Vf changes. Therefore, as described above, the measurement voltage V1 is set to several measurement voltages having different voltage values, and the initial element current If1
Is preferably measured and stored.

However, in the case of controlling with the peak value, similarly to the case of controlling with the pulse width, a certain measured voltage value V
The element current for only 1 may be used as the initial element current If1.

Even when driving is performed by controlling the amount of emitted electrons by the peak value (voltage value), the driving voltage Vf is set to a value lower than the above-described maximum voltage value (Vmax). . Here, in the device manufacturing process, when no voltage is applied to the device after the activation process, the maximum voltage value applied to the device in the activation process corresponds to Vmax.

Then, after the first measurement step, the driving of the electron-emitting device is started.

When driving the element, always
Alternatively, the element current is periodically measured by the ammeter 50 at predetermined intervals (second measurement step). The presence or absence of the element characteristic fluctuation is determined by the element current If2 when the same voltage value as the measurement voltage V1 applied in the first measurement step is applied to the element.

Then, the element current monitoring controller 57 determines that the element current If2 observed in the second measuring step is a predetermined value (preferably 5% or more of the initial element current) compared to the initial element current If1. When the device current has increased, more preferably when the device current has increased by 3% or more of the initial device current). Driving (voltage applying step) is performed.

In the simplest case, when it is determined that the element current If2 observed in the second measurement step is larger than the initial element current If1, the following characteristic recovery drive (voltage application step) is performed. Should be done.

Characteristics recovery driving method A: Before the first measurement step (including the element manufacturing step), the maximum voltage value Vmax applied to the element is equal to or lower than the maximum voltage value Vmax and the element driving voltage Vf The power supply 51 is instructed to apply a higher voltage V2 for an appropriate time.

As described above, when the amount of electrons emitted from the device is controlled by the pulse peak value applied to the device, the potential Vf applied to the device during driving is not constant. Therefore, when controlling with the pulse peak value applied to the element, the voltage V2 should be higher than the highest voltage value in a predetermined range of the element driving voltage value Vf. Is preferred.

Characteristic recovery driving method B: Before the first measurement step (including the element manufacturing step), the maximum power applied to the element: Pmax or less, and the maximum power applied to the element in the first measurement step was applied to the element. The power supply 51 is instructed to apply the power: P2 which is higher than the power: P1 to the element.

In the case where the element is driven by applying a pulse voltage, the “power” is defined as the area of the waveform of one pulse (the integral of the voltage value applied in one pulse with respect to time). Value). For a constant-voltage square-wave pulse,
“Power” corresponds to (peak value × pulse width) of the pulse. However, it is preferable to apply a voltage V2 higher than the measurement voltage V1 applied in the first measurement step for a short time, rather than applying a low voltage for a long time.

For this reason, it is more preferable to apply a pulse having both the elements A and B to the element. That is,
A voltage V1 which is equal to or higher than the power of the pulse applied in the first measuring step and which is applied in the first measuring step.
It is more preferable to apply a pulse having a peak value of a higher voltage V2.

Also in this case, as described above, when the amount of electrons emitted from the element is controlled by the pulse peak value applied to the element, the potential Vf applied to the element during driving is not constant. . Therefore, when controlling with the pulse peak value applied to the element, the voltage V2 should be higher than the highest voltage value in a predetermined range of the element driving voltage value Vf. Is preferred.

In this manner, by applying the voltage V2 and / or the power: P2 to the element, fluctuations in element characteristics can be suppressed.

As a result, the element characteristics characterized by the voltage V2 can be refreshed (changed). This refreshing mechanism is considered to be due to the completely or partially removed carbon or carbon compound newly deposited in the vicinity of the electron-emitting portion 5.

After the characteristic recovery drive, the drive voltage of the element is returned to the normal drive voltage Vf.

By the characteristic recovery driving, an element current corresponding to the voltage Vf in the voltage-element current characteristic characterized by the voltage V2 can be obtained. As a result, an increase in element current observed before performing the characteristic recovery driving is suppressed.

Then, again, the first measurement step described above,
A second measuring step and a voltage applying step (characteristic recovery driving) are performed.

By repeating these series of processes each time the rise of the device current If is measured, the device current If
Can be effectively suppressed.

Further, once the first measurement step is performed,
After performing the voltage application step (characteristic recovery drive), the first measurement step may not be performed. That is, the first measuring step → the second measuring step → the voltage applying step → the second measuring step → the voltage applying step → the second measuring step → the voltage applying step, etc.
After the voltage application step (characteristic recovery drive) is performed once, the second measurement step and the voltage application step (characteristic recovery drive)
Can be repeated only.

The element current If2 and / or emission current Ie2 measured in the second and subsequent second measurement steps are also compared with the element current If1 and / or emission current Ie1 measured in the first measurement step performed first. By doing so, it is possible to determine the necessity of the above-described characteristic recovery.

When the first measuring step is performed each time after the voltage applying step (characteristic recovery driving), the values (If1, Ie1) obtained in the first measuring step may vary. . Therefore, the first measurement step is performed only once,
This value is referred to as a value (If) obtained each time the second measurement step is performed.
2, Ie2).

Further, in the characteristic recovery driving, when the element is driven by a pulse voltage, for example, the application timing of the voltage V2 and the application timing of the voltage V2 are controlled so that the amount of the emitted charges captured by the anode electrode 54 does not fluctuate with time. It is preferable to change the pulse width.

In the driving method according to the present embodiment described above, the device current is monitored (first and second measurement steps).
Then, the characteristic recovery drive (voltage application step) is performed.
However, when the increase in the emission current is detected by the emission current monitoring controller 58, an instruction may be given to the power supply 51 to perform the characteristic recovery drive (voltage applying step). In that case, in the same manner as the measurement of the initial element current If1,
The initial emission current Ie may be used as the first measurement step.

It is also possible to use the element current monitoring controller 57 and the emission current monitoring controller 58 in combination to perform the same control as described above.

The above-described control is performed when one of the element current and the emission current increases above a preset threshold, or the control is performed when both increase above a certain threshold. Good.

In any case, according to the driving method of the present embodiment, the voltage V2 and / or the power P2 are applied as needed. Therefore, as compared with a method in which a voltage higher than the drive voltage Vf is applied at a predetermined interval, deterioration of element characteristics can be suppressed as much as possible, and the element can be driven stably for a long time.

FIG. 7 is a flowchart showing the processing by the element current monitoring controller 57 which is an example of the present embodiment. Here, a case where the control (drive) of the emission current Ie from the electron-emitting device is controlled by the pulse width (the drive voltage Vf is constant) will be described.

First, in step S1, it is determined whether or not it is the timing of the measurement time. If it is the measurement timing, the process proceeds to step S2, and the element current If2 is measured by the ammeter 50 (second measurement step). Then, the value of the measured element current If2 is input.

Then, the process proceeds to a step S3, wherein it is determined whether or not the value of the input element current If2 is larger than a predetermined current If1 (the previously measured "initial element current"). In step S3, preferably, when it is determined that the element current If2 measured in the second measurement step is larger than the previously measured “initial element current If1” by 5% or more, step S5 (the characteristic described above) is performed. (Recovery drive). Alternatively, the element current If2 measured in the second measurement step is the “initial element current If1” measured in advance.
If it is determined that the value is 3% or more, step S5
It is more preferable to shift to (the above-described characteristic recovery driving).

If the device current If2 is larger than If1 in step S3, the process proceeds to step S5, in which the output voltage value of the power supply 51 is set to the above-described voltage V2, or the output power is set to the above-described power P2, and the power supply 51 is pulsed. Control is performed such that a voltage signal is generated and applied to the element (the characteristic recovery drive described above is performed). On the other hand, when the value of the element current If2 is equal to or smaller than the predetermined current If1 in Step S4, the process proceeds to Step S4.
The output voltage value of the power supply 51 is not changed (the characteristic recovery drive described above is not performed).

Similarly, in the case of the emission current monitoring controller 58, it is determined in step S3 whether the value of the emission current Ie2 is larger than a predetermined emission current Ie1, and if it is larger, the flow proceeds to step S5. When the current is equal to or less than Ie1, the control can be similarly performed by proceeding to step S4. Also, in the case where the above-described characteristic recovery drive is performed based on the increase in the emission current Ie, the element current Ie2 measured in the second measurement step is 5% less than the “initial emission current Ie1”.
When it is determined that the value is larger than the above, it is preferable to shift to step S5 (the above-described characteristic recovery drive). Moreover,
It is more preferable to shift to step S5 (the above-described characteristic recovery drive) when it is determined that the current is greater than the “initial emission current Ie1” by 3% or more.

By performing the above-described characteristic recovery driving during driving, it is possible to obtain an electron-emitting device that has little fluctuation in electron-emitting characteristics and is stable for a long time. Here, an example in which the second measurement step is performed at regular intervals has been described, but the second measurement step may be performed each time the drive voltage Vf is applied to the element.

Next, application examples of the electron-emitting device to which the driving method according to the present embodiment can be applied will be described below. By arranging a plurality of electron-emitting devices of the present embodiment on a substrate, for example, an electron source or an image forming apparatus can be configured.

Various arrangements of these electron-emitting devices can be adopted. As an example, each of a large number of electron-emitting devices arranged in parallel is connected at both ends, a large number of rows of electron-emitting devices are arranged (referred to as a row direction), and a direction perpendicular to the wiring (referred to as a column direction). There is a ladder-type arrangement in which electrons from the electron-emitting device are controlled and driven by a control electrode (also referred to as a grid) disposed above the electron-emitting device.
Separately, a plurality of electron-emitting devices are arranged in a matrix in the x-direction and the y-direction, and one of the electrodes of the plurality of electron-emitting devices arranged in the same row is commonly connected to a wiring in the x-direction. One example is one in which the other of the electrodes of the plurality of electron-emitting devices arranged in a row is commonly connected to a wiring in the y-direction. This is called a simple matrix arrangement. First, the simple matrix arrangement will be described in detail below.

The electron-emitting device applicable to this embodiment has the characteristics (i) to (iii) as described above. That is, the emitted electrons from the electron-emitting device can be controlled by the peak value and the width of the pulse-like voltage applied between the opposing device electrodes when the applied device voltage is equal to or higher than the threshold voltage. On the other hand, below the threshold voltage, almost no electrons are emitted. According to such characteristics, even when a large number of electron-emitting devices are arranged, if a pulse-like voltage is appropriately applied to each of the devices, the surface conduction electron-emitting device is selected according to an input signal, and the electron emission amount is selected. Can be controlled.

Hereinafter, based on this principle, an electron source substrate obtained by arranging a plurality of electron-emitting devices of the present embodiment will be described with reference to FIG. FIG. 8 is a plan view of an electron source in which these electron-emitting devices are arranged in a matrix.

In FIG. 8, reference numeral 71 denotes an electron source substrate, 72 denotes an x-direction wiring, and 73 denotes a y-direction wiring. 74 is an electron-emitting device, and 75 is a connection. Note that these electron-emitting devices 74
May be either the above-mentioned flat type or vertical type.

The m x-direction wirings 72 are Dx1, Dx2,
…, Dxm, these wirings are vacuum deposition method, printing method,
It can be made of a conductive metal or the like formed by a sputtering method or the like. The material, thickness and width of these wirings are
Designed as appropriate. Further, the y-direction wiring 73 includes Dy1, Dy2,
, Dyn and are formed in the same manner as the x-direction wiring 72. An interlayer insulating layer (not shown) is provided between the m x-directional wirings 72 and the n y-directional wirings 73, and these insulating layers electrically separate them (m, n). Are both positive integers).

An interlayer insulating layer (not shown) is made of SiO 2 or the like formed by using a vacuum deposition method, a printing method, a sputtering method, or the like. For example, the film is formed in a desired shape on the entire surface or a part of the substrate 71 on which the x-direction wiring 72 is formed. In particular, these films are formed so as to withstand the potential difference at the intersection of the x-direction wiring 72 and the y-direction wiring 73. The thickness, material, and manufacturing method are appropriately set. x
The direction wiring 72 and the y-direction wiring 73 are respectively drawn out as external terminals. Further, these electron-emitting devices 74
Each of a pair of electrodes (2, 3 in FIG. 1)
One of the m x-directional wirings 72 and one of the n y-directional wirings 73 are electrically connected to a connection 75 made of a conductive metal or the like.

The material forming the x-direction wiring 72 and the y-direction wiring 73, the material forming the connection 75, and the material forming the pair of element electrodes 2 and 3 have some or all of the same constituent elements. Or each may be different. These materials are appropriately selected, for example, from the above-described materials of the electrodes 2 and 3. Here, the materials constituting the electrodes 2 and 3
When the materials of the wirings 72, 73, and 75 are the same, the wiring connected to the electrodes 2 and 3 can be called an electrode.

A scanning signal applying means (for example, a scanning circuit 1 shown in FIG. 13) for applying a scanning signal for selecting each row of the electron-emitting devices 74 arranged in the x direction is provided on the x-direction wiring 72.
02) is connected. On the other hand, the y-direction wiring 73 is connected to a modulation signal generating means (for example, the modulation circuit 107 in FIG. 13) for modulating each column of the electron-emitting devices 74 arranged in the y-direction according to an input signal. The driving voltage applied to each electron-emitting device is supplied as a difference voltage between a scanning signal and a modulation signal applied to the device.

In the above configuration, individual elements can be selected and driven independently using a simple matrix wiring.

FIGS. 9 to 13 show an image forming apparatus constructed using such an electron source having a simple matrix arrangement.
This will be described with reference to FIG.

FIG. 9 is a schematic diagram showing an example of the display panel 101 of the image forming apparatus according to the present embodiment, and FIG.
10B is a schematic diagram of a fluorescent film used in the image forming apparatus of FIG. 11 is a diagram showing a configuration of a manufacturing apparatus of the image forming apparatus, FIG. 12 is a wiring diagram for forming and activating steps, and FIG. 13 is a drive circuit for performing display according to an NTSC television signal. FIG. 4 is a block diagram showing an example of the above.

In FIG. 9, reference numeral 71 denotes an electron source substrate on which a plurality of electron-emitting devices are arranged; 81, a rear plate on which the electron source substrate 71 is fixed; 86, a fluorescent film 84 on the inner surface of a glass substrate 83;
And a face plate on which a metal back 85 and the like are formed. Reference numeral 82 denotes a support frame, and a rear plate 81 and a face plate 86 are joined to the support frame 82 using low melting point frit glass or the like. Reference numeral 74 denotes an electron-emitting device, which corresponds to the electron-emitting device shown in FIGS. 7
Each of 2 and 73 is an x-direction wiring and a y-direction wiring connected to a pair of electrodes of the electron-emitting device.

The envelope 88 includes the face-plate 86, the support frame 82, and the rear plate 81 as described above. Since the rear plate 81 is provided mainly for the purpose of reinforcing the strength of the substrate 71, if the substrate 71 itself has sufficient strength, the separate rear plate 81 can be unnecessary. That is, the support frame 82 is directly sealed to the substrate 71, and the envelope 8 is formed by the face plate 86, the support frame 82 and the substrate 71.
8 may be configured. On the other hand, face-plate 86,
By providing a support (not shown) called a spacer between the rear plates 81, an envelope 88 having sufficient strength against atmospheric pressure can be formed.

FIGS. 10A and 10B are schematic diagrams showing the arrangement of the fluorescent films.

In the case of monochrome, the fluorescent film 84 can be composed of only a phosphor. In the case of a color fluorescent film, it can be composed of a black conductive material 91 called a black stripe or a black matrix and a fluorescent material 92 depending on the arrangement of the fluorescent materials. The purpose of providing these black stripes and black matrix is to make the color separation between the phosphors 92 of the necessary three primary color phosphors black in color display so that color mixing and the like are inconspicuous. This is to suppress a decrease in contrast due to reflection of external light in the above. As a material for the black stripe, a material having conductivity and a small amount of light transmission and reflection can be used in addition to a commonly used material containing graphite as a main component.

As a method of applying the phosphor on the glass substrate 83, a precipitation method, a printing method, or the like can be adopted regardless of monochrome or color. Usually, a metal back 85 is provided on the inner surface side of the fluorescent film 84. The purpose of providing the metal back 85 is to improve the brightness by reflecting the light toward the inner surface side of the light emitted from the phosphor toward the face plate 86 in a mirror-like manner, and to serve as an electrode for applying an electron acceleration voltage. This is for protecting the phosphor 92 from damage due to collision of negative ions generated in the envelope 88. After the fluorescent film 84 is formed, the metal back 85 performs a smoothing process (usually called “filming”) on the inner surface of the fluorescent film 84, and then aluminum (Al) is formed by vacuum evaporation or the like. It can be created by depositing.

The face plate 86 may be provided with a transparent electrode (not shown) on the outer surface of the fluorescent film 84 in order to further enhance the conductivity of the fluorescent film 84.

When the envelope 88 is sealed as described above, in the case of color, the phosphors of each color must correspond to the electron-emitting devices, and sufficient alignment is indispensable.

Next, an example of a method for manufacturing the display panel 101 shown in FIG. 9 will be described below.

FIG. 11 is a block diagram showing an outline of a manufacturing apparatus for executing this manufacturing method.

This envelope 88 is connected to a vacuum chamber 133 via an exhaust pipe 132,
4 is connected to the exhaust device 135. A pressure gauge 136, a quadrupole mass analyzer 137, and the like are attached to the vacuum chamber 133 to measure the internal pressure and the partial pressure of each component in the atmosphere. This display panel 1
Since it is difficult to directly measure the pressure and the like inside the envelope 88 of FIG. 01, the pressure and the like inside the vacuum chamber 133 are measured to control the processing conditions. This vacuum chamber 13
3 is connected to a gas introduction line 138 for introducing a necessary gas into the vacuum chamber 133 to control the atmosphere. An introduction substance source 140 is connected to the other end of the gas introduction line 138, and the introduction substance is stored in an ampule or a cylinder. Further, in the middle of the gas introduction line 138, a gas introduction control means 139 for controlling a rate at which the introduced substance is introduced is provided. As the gas introduction control means 139, specifically, a valve such as a slow leak valve capable of controlling the flow rate, a mass flow controller, or the like can be used according to the type of the substance to be introduced.

With the manufacturing apparatus shown in FIG. 11, the inside of the envelope 88 is evacuated and energization forming is performed. At this time, for example, as shown in FIG. 12, the y-direction wiring 73 is connected to the common electrode 141, and a voltage pulse is simultaneously applied by the power source 142 to the element connected to one of the x-direction wirings 72, thereby Can be formed. Conditions such as the shape of the voltage pulse and the determination of the end of the processing are as follows.
What is necessary is just to select according to the method already described about the forming of an individual element. Further, by sequentially applying (scrolling) a pulse having a phase shifted to the plurality of x-direction wirings 72, it is possible to form the elements connected to the plurality of x-direction wirings 72 collectively. In FIG. 12, reference numeral 143 denotes a current measuring resistor, and 144 denotes a current measuring oscilloscope. After the completion of the forming, the above-described activation step is performed on the element of the type requiring the above-described activation step.

In this activation step, after the inside of the envelope 88 is sufficiently evacuated, the organic substance is introduced into the gas introduction line 13.
Introduced from 8. Alternatively, as described in the method of activating the individual elements, first, exhaust may be performed by an oil diffusion pump or a rotary pump, and thereby, an organic substance remaining in a vacuum atmosphere may be used. In addition, substances other than organic substances may be introduced as necessary. A voltage is applied to each electron-emitting device in the atmosphere containing the organic substance formed in this manner. As a result, carbon or a carbon compound, or a mixture of both, is formed in the gap 6 and the gap 6 formed by the forming.
, And the amount of emitted electrons for a predetermined voltage drastically increases. In this case, the voltage may be applied by simultaneously applying a voltage pulse to the elements connected to one x-direction wiring by the same connection as in the above-described forming.

After the activation step, a stabilization step is preferably performed as in the case of an individual element. In this stabilization step, the envelope 88 is heated and maintained at 80 to 250 ° C. while the exhaust pipe 13 by the exhaust device 135 that does not use oil, such as an ion pump or a sorption pump.
After exhausting through 2 to make the atmosphere sufficiently low in organic substances, the exhaust pipe is heated with a burner, melted and sealed. In order to maintain the pressure after the envelope 88 is sealed, a getter process may be performed. This is because the getter placed at a predetermined position (not shown) in the envelope 88 by heating using resistance heating or high-frequency heating immediately before or after the envelope 88 is sealed. Is a process of forming a vapor-deposited film by heating. This getter usually contains Ba or the like as a main component, and maintains the atmosphere in the envelope 88 by the adsorption action of the deposited film.

Next, a display panel (flat panel display) constructed using electron sources in a simple matrix arrangement
Next, a configuration example of a driving circuit for performing television display based on an NTSC television signal will be described with reference to FIG.

In FIG. 13, reference numeral 101 denotes the above-described display panel (envelope 88), 102 denotes a scanning circuit, 103 denotes a control circuit, and 104 denotes a shift register. 105 is a line memory, 106 is a synchronizing signal separation circuit, 107 is a modulation signal generator, and Vx and Va are DC voltage sources. The display panel 101 is connected to an external electric circuit via the row (x-direction) terminals Dox1 to Doxm, the column (y-direction) terminals Doy1 to Doyn, and the high-voltage terminal Hv as described above. The row terminals Dox1 to Doxm are provided with scanning for sequentially driving electron sources provided on the display panel 101, that is, electron emission element groups arranged in a matrix of m rows and n columns, one row at a time (n elements). A signal is applied.

On the other hand, to the column terminals Dy1 to Dyn, a modulation signal corresponding to an image signal for controlling output electrons of each of the electron-emitting devices in one row selected by the scanning signal is applied. A DC voltage of, for example, 10 kV from the DC voltage source Va is applied to the high-voltage terminal Hv by the face plate 86 (FIG. 5).
, Which is an acceleration voltage for applying sufficient energy to electrons emitted from the electron-emitting device to excite the phosphor.

Next, the scanning circuit 102 will be described.
The scanning circuit 102 includes m switching elements inside (in the drawing, S1 to Sm are schematically shown). Each of these switching elements selects either the output voltage of the DC voltage source Vx or 0 V (ground level) and is electrically connected to the row terminals Dx1 to Dxm of the display panel 101. Each of the switching elements S1 to Sm operates based on a control signal Tscan (horizontal synchronization signal) output from the control circuit 103, and can be configured by combining switching elements such as FETs, for example.

In the case of the present embodiment, the DC voltage source Vx generates a voltage applied to the unselected row wiring based on the characteristics (electron emission threshold voltage) of the surface conduction electron-emitting device. In addition, the driving voltage (difference voltage of the modulation signal) applied to the element that is not scanned is set to output a constant voltage that is equal to or lower than the emission threshold voltage (Vth) of the electron-emitting element.

The control circuit 103 has a function of matching the operation of each unit so that an appropriate display is performed based on an externally input image signal. The control circuit 103 generates control signals such as a horizontal synchronization signal Tscan, a shift clock Tsft, and a memory latch signal Tmry for each unit based on the synchronization signal Tsync sent from the synchronization signal separation circuit 106.

The synchronizing signal separation circuit 106 is a circuit for separating a synchronizing signal component and a luminance signal component from an NTSC television signal input from the outside, and uses a general frequency separation (filter) circuit or the like. Can be configured. Although the synchronization signal Tsync separated by the synchronization signal separation circuit 106 includes a vertical synchronization signal and a horizontal synchronization signal, it is illustrated here as a Tsync signal for convenience of explanation. The luminance signal component of the image separated from the NTSC television signal is D for convenience.
Expressed as an ATA signal. This DATA signal is input to the shift register 104.

The shift register 104 is for serially / parallel-converting a DATA signal input serially in time series for each line of an image, and is based on a control signal Tsft sent from the control circuit 103. It operates (that is, the control signal Tsft functions as a shift clock of the shift register 104). The image data for one line (corresponding to the drive data for n electron-emitting devices) thus serial-parallel-converted are Id1 to Id1.
The shift register 104 outputs to the line memory 105 as n parallel signals of dn. Line memory 105
Is a storage circuit for storing image data for one line for a required time only, and stores image data Id1 to Idn for one line as appropriate according to a control signal Tmry sent from the control circuit 103. Thus, the line memory 10
5 are output as image data I′d1 to I′dn and input to the modulation signal generator 107.

The modulation signal generator 107 outputs the image data I'd
A signal source for appropriately driving and modulating each of the electron-emitting devices in accordance with each of 1 to I'dn, and an output signal thereof is applied to the electron-emitting devices of the display panel 101 through the column terminals Doy1 to Doyn. .

The switching of the drive voltage waveform (the above-described characteristic recovery drive) in the present embodiment is performed by the modulation signal generator 1.
07 may be performed. That is, when the modulation signal generator 107 performs modulation by pulse width modulation, the waveform value of the output pulse voltage is changed to the voltage V during normal driving.
Set to f. When the element current monitoring controller 57 or the emission current monitoring controller 58 detects that the element current If or the emission current Ie has increased to a predetermined value or more, the modulation signal generator 1 via the control circuit 103.
07 is the output voltage V2 or the power P2 described above.
What is necessary is just to control so that it may become. As a result, the modulation signal pulse is replaced or superimposed on the voltage value.

This modulation method will be described in more detail. As described above, the electron-emitting device applicable to the present embodiment has the following basic characteristics with respect to the emission current Ie. That is, electron emission has a clear threshold voltage Vth, and electron emission occurs only when a voltage equal to or higher than the threshold voltage Vth is applied. For a voltage equal to or higher than the electron emission threshold voltage, the emission current also changes according to the change in the voltage applied to the element. From this, when a pulse-like voltage is applied to this element, for example, when a voltage lower than the electron emission threshold is applied, electron emission does not occur, but when a voltage higher than the electron emission threshold voltage is applied, electrons are emitted. Is output. At this time, it is possible to control the amount of electrons output by changing the pulse peak value Vm. In addition, by changing the pulse width Pw, it is possible to control the total amount of the outputted electrons. Therefore, a voltage modulation method, a pulse width modulation method, or the like can be adopted as a method of modulating the electron-emitting device according to the input signal.

When implementing this voltage modulation method,
A voltage pulse of a fixed length as the modulation signal generator 107;
And a voltage modulation type circuit that generates a pulse in which the above-described voltage V2 or a pulse having power P2 is replaced or superimposed on the voltage pulse and modulates the peak value of the pulse appropriately according to input data. Can be used.

When the pulse width modulation method is adopted,
The modulation signal generator 107 generates a voltage pulse having a constant peak value and a pulse obtained by replacing or superimposing the above-described voltage pulse with the voltage V2 or the pulse having the power P2, and appropriately generating a voltage according to input data. A pulse width modulation type circuit that modulates a pulse width can be used.

The shift register 104 and the line memory 10
5 can be a digital signal type or an analog signal type. This is because the serial / parallel conversion and storage of the image signal may be performed at a predetermined speed. When the digital signal type is used, it is necessary to convert the output signal DATA of the synchronization signal separation circuit 106 into a digital signal.
This can be achieved by providing an A / D converter at the output of the synchronization signal separation circuit 106.

In this connection, the circuit used for the modulation signal generator 107 differs slightly depending on whether the output signal of the line memory 105 is a digital signal or an analog signal. That is, in the case of the voltage modulation method using a digital signal,
For example, a D / A conversion circuit is used as the modulation signal generator 107, and an amplification circuit and the like are added as necessary. In the case of the pulse width modulation method, the modulation signal generator 107 includes, for example, a high-speed oscillator, a counter for counting the number of waves output from the oscillator, and a comparison between the output value of the counter and the output value of the memory. A circuit in which a comparator (comparator) is combined is used. If necessary, an amplifier for amplifying the pulse width modulated signal output from the comparator to a driving voltage of the surface conduction electron-emitting device can be added.

In the case of the voltage modulation method using an analog signal, an amplification circuit using, for example, an operational amplifier can be used as the modulation signal generator 107, and a level shift circuit or the like can be added as necessary. In the case of the pulse width modulation method, for example, a voltage controlled oscillator (VOC)
And, if necessary, an amplifier for amplifying the voltage up to the drive voltage of the electron-emitting device can be added.

In the image display apparatus using the display panel according to the present embodiment having such a configuration, each of the electron-emitting devices has row terminals Dox1 to Doxm and column terminals Dx1 outside the container.
By applying a voltage via oy1 to Doyn, electron emission occurs. Metal back 8 via high voltage terminal Hv
5, or apply a high voltage to a transparent electrode (not shown) to accelerate electrons. The electrons accelerated in this way collide with the fluorescent film 84 and emit light to form an image.

The configuration of the image forming apparatus described here is an example of an image forming apparatus applicable to the present embodiment, and various modifications can be made based on the technical idea of the present embodiment. The input signal has been described in the NTSC system, but the input signal is not limited to this, and PAL, SECA
In addition to the M system, a TV signal composed of a larger number of scanning lines (for example, a high-quality TV including the MUSE system)
A method can also be adopted.

Next, a ladder-type electron source and an image forming apparatus using the same will be described with reference to FIGS. 14 and 15. FIG.

FIG. 14 is a schematic diagram showing an example of the ladder-type arrangement of the electron source according to the present embodiment.

In the figure, reference numeral 110 denotes an electron source substrate;
Denotes an electron-emitting device. Dx1 to Dx10 (112) are common wirings for connecting the electron-emitting devices 111. Here, a plurality of electron-emitting devices 111 are arranged on the substrate 110 in parallel in the x direction (this is called an element row). A plurality of the element rows are arranged to form an electron source. By applying a drive voltage between the common wires of each element row, each element row can be driven independently. That is, a voltage equal to or higher than the electron emission threshold (Vth) is applied to an element row from which electrons are to be emitted, and a voltage equal to or lower than the electron emission threshold is applied to an element row that does not emit electrons. The common wirings Dx2 to Dx9 between the element rows are
For example, Dx2 and Dx3 can be the same wiring.

FIG. 15 is a schematic diagram showing an example of the structure of the display panel 101a provided with the ladder-type electron source shown in FIG.

Reference numeral 120 denotes a grid electrode, 121 denotes a hole through which electrons pass, and 122 denotes an out-of-container terminal composed of Dox1, Dox2,..., Doxm. 123 is a grid electrode 1
, Gn connected to the outside of the container. In FIG. 15, the same parts as those shown in the above-mentioned figures are denoted by the same reference numerals. The major difference between the display panel 101a shown here and the display panel 101 having the simple matrix arrangement shown in FIG.
0, and whether or not the grid electrode 120 is provided between the face plate 86.

Referring to FIG. 15, a grid electrode 120 is provided between a substrate 110 and a face plate 86. The grid electrode 120 is for modulating the electrons emitted from the electron-emitting devices, and corresponds to each element in order to allow the electrons to pass through a stripe-shaped electrode provided orthogonally to the ladder-shaped element rows. 1 circular opening 1 each
21 are provided. The shape and arrangement position of these grid electrodes 120 are not limited to those shown in FIG. For example, a large number of passage openings may be provided in a mesh shape as the opening 121, and the grid electrode 120
May be provided around or near the electron-emitting device.

Each of the row terminal 122 and the grid terminal 123 outside the container is connected to, for example, the scanning circuit 10 described above.
2. It is electrically connected to the modulation signal generator 107.

In the display panel 101a of the present embodiment,
In synchronization with sequentially driving (scanning) the element rows one by one,
Modulation signals for one line of an image are simultaneously applied to the columns of the grid electrodes 120. This makes it possible to control the irradiation of the phosphors with the electrons emitted from each element and display an image one line at a time. Display panel 101a of this embodiment
The image forming apparatus using the image forming apparatus may be used as an image forming apparatus as an optical printer configured using a photosensitive drum or the like, in addition to a display device for a television broadcast, a display device for a video conference system, a computer, and the like. it can.

Hereinafter, the present embodiment will be described in detail with reference to specific examples. However, the present embodiment is not limited to these examples, but falls within a range where the object of the present embodiment is achieved. This includes the case where each element is replaced or the design is changed.

Example 1 In Example 1, the electron-emitting device shown in FIG. 20 was manufactured. In order to compare the case where the driving method according to the present embodiment is applied and the case where the present embodiment is not applied for comparison, two elements were created (element A and element B, respectively). Will be called). The results of experiments performed on the electron emission characteristics and the like of each electron-emitting device will be described.

In the drawing, W1 is the width of the electrodes 2 and 3, W2 is the width of the conductive film 4, L is the distance between the electrodes 2 and 3, and d is the width of the electrodes 2 and 3.
3 represents the thickness. Further, since the same shape, configuration, and process of each of the elements A and B are used until the stabilization process described later, the same shape, configuration, and process are used.
In particular, the description will be made without distinguishing between the two.

Hereinafter, a specific description will be given with reference to FIG. 21 showing a procedure of a method of manufacturing each element used in the first embodiment.

(1) A quartz substrate was used as the substrate 1, and this was sufficiently washed with a detergent, pure water and an organic solvent, and then 5 nm thick Ti and 50 nm thick P were formed by vacuum evaporation.
t were sequentially deposited. Then, after forming a pattern to be a gap L between the electrodes 2 and 3 and the photoresist,
Electrodes 2 and 3 were formed by dry etching.
The distance L between the electrodes 2 and 3 is 3 μm (FIG. 21).
(A)).

Thereafter, a lift-off Cr film (not shown) was vacuum deposited to a thickness of 50 nm for the purpose of patterning the conductive film 4. At this time, the size of the opening of the Cr film corresponding to the width W2 of the conductive film 4 was set to 300 μm.

(2) On the substrate 1 on which the electrodes 2 and 3 are formed,
An organic palladium solution (manufactured by Okuno Pharmaceutical Co., Ltd., ccp-4230) was spin-coated with a spinner and allowed to stand to form an organic Pd thin film. Thereafter, the organic Pd thin film is
Heating and baking treatment in air at 15 ° C. for 15 minutes
A conductive film 4 made of O was formed. The thickness of the conductive film 4 was about 7 nm.

Thereafter, the Cr film was wet-etched with an acid etchant, and the conductive film 4 was lifted off to obtain a conductive film 4 having a desired pattern (FIG. 21).
(B)).

(3) Next, both the devices A and B were installed in the vacuum apparatus 55 of the evaluation and measurement system shown in FIG. Then, the device voltage Vf
A voltage was applied between the electrodes 2 and 3 by a power source 51 for applying a current, and a current was passed through the conductive film 4 to form a first gap 6 (forming process) (FIG. 21C). In this forming process, the voltage waveforms shown in FIG.

In the first embodiment, T1 in FIG.
Forming was performed while increasing the pulse peak value by 0.1 V for m seconds and T2 of 10 ms. During the forming process, a resistance measuring pulse of 0.1 V was simultaneously inserted between T2 to measure the resistance. The forming was terminated when the measured value of the resistance measuring pulse became about 1 MΩ or more, and the application of the voltage to the element was terminated at the same time.

(4) Subsequently, both the devices A and B are vacuum devices 5
1.3 x 1 acetone
The activation process was performed by introducing 0 to the third power [Pa] and applying a pulse voltage between the electrodes 2 and 3 of the devices A and B for about 30 minutes. In the first embodiment, as shown in FIG. 22B, a positive pulse of a rectangular wave and a pulse of a negative voltage having a reverse polarity and the same waveform and the same absolute value of the voltage are alternately applied. Note that T1 was 1 ms, T2 was 10 ms, and the peak value (absolute value) of the pulse was 15 V for both elements A and B.

In this step, the carbon film 10 is formed on the conductive film 4 in the first gap 6 and in the vicinity of the first gap, and at the same time, the second gap 7 having a width smaller than that of the first gap 6.
Was formed (FIG. 21D).

(5) Subsequently, after the acetone in the vacuum vessel was evacuated, the element section and the entire vacuum vessel were heated at 150 ° C. for 2 hours, and the inside of the vacuum device 55 was 1.3 × 10 −6 [P
a], and a stabilization step was performed.

After the stabilization step, the device current I of each of the electron-emitting devices A and B is maintained while maintaining the degree of vacuum.
f, emission current Ie was measured. The measurement conditions were such that the distance H between the anode 54 and the electron-emitting device was 5 mm, and the potential of the anode 54 was 1 KV.

First, for the element A, the pulse width T1 and the pulse interval T2 are calculated by using the waveform shown in FIG.
Assuming that T1 is 0.2 ms and T2 is 10 ms,
Three pulses having a peak value of 15 V were applied, and the emission current Ie at that time was measured. Subsequently, the pulse width T1 and the pulse interval T2 were respectively set to T1 for 0.2 ms and T2 to 10 ms.
Assuming m seconds, three pulses with a peak value of 14 V are added,
When the emission current Ie at that time was measured (first measurement step), the value was about 40% as compared with when a pulse having a peak value of 15 V was applied. Therefore, when a pulse having a peak value of 15 V is applied, if the pulse width is about 40% of T1, the charge captured by the anode electrode 54 per pulse may be substantially equal to that in the case of 14 V. confirmed.

Next, the characteristics of the devices A and B were evaluated for 500 hours.

As the driving pulse waveform, the waveform shown in FIG. 4A is basically used for both the substrates A and B, and the peak value Vf of the driving voltage is set to 14V. Further, the pulse width T1 and the pulse interval T2 are respectively T1 of 0.2 ms and T2 of 1
0 ms.

For the element A, an increase in the element current If was monitored by the element current monitoring controller 57. When detecting an increase in the device current of 3%, the power supply 51 for applying the device voltage to the electron-emitting device emits one pulse having a peak value of 15 V and a peak value of the drive voltage Vf. A command was issued to apply the voltage in place of the 14 V pulse, and the voltage was applied (characteristic recovery driving). The pulse width of the peak value of 15 V is 40% of 0.2 ms, that is, 0.08.
m seconds.

For the element B, the characteristic recovery driving operation performed on the element A was not performed, and the peak value was 14
The application of a constant pulse of V was continued. The device current If and the emission current Ie for the devices A and B were measured at the time when the peak value of 14 V was applied.

According to the above experiment, a driving experiment was performed for 500 hours.
In contrast to the fluctuation caused by the increase in f, the element A generated only a fluctuation of about 3%, which was within the control range of the drive. In addition, the emission current Ie also fluctuated by only about 3%, and the device could be driven extremely stably.

When the peak value of each of the elements A and B is 14 V, the element current If has a characteristic of increasing.
This is considered to be due to incomplete removal of organic substances.

That is, according to the driving method of the present embodiment,
Even when the device current If is increased due to incomplete removal of an organic substance or the like, the device can be driven extremely stably for a long time.

Example 2 An element C was prepared by performing the same steps as in Example 1 up to the stabilization step.

By applying a voltage to the element C while maintaining the degree of vacuum as it is even after the stabilization step, the element current If,
The emission current Ie was measured.

First, for the element C, the pulse width T1 and the pulse interval T2 are calculated by using the waveform shown in FIG.
Assuming that T1 is 0.2 ms and T2 is 10 ms,
Three pulses having a peak value of 15 V were applied. Then, the emission current Ie at that time was measured. Subsequently, the pulse width T1
And the pulse interval T2, T1 is 0.2 ms each,
With T2 set to 10 ms, three pulses having a peak value of 14 V were applied, and the emission current Ie at that time was measured (first measurement step). As a result, the value was about 40% as compared with when a pulse having a peak value of 15 V was applied. Thus, when a pulse having a peak value of 15 V is applied, if the pulse width is about 40% as compared with the case of 14 V, the charge captured by the anode electrode 54 per pulse is 14 V. It was confirmed that they were almost equal.

Next, the characteristics of the device C were evaluated for 500 hours.

The driving pulse waveform is basically the same as that shown in FIG.
And the peak value of the drive voltage Vf is 14 V
And The pulse width T1 and the pulse interval T2 were basically set to 0.2 ms for T1 and 10 ms for T2, respectively. For the element C, an increase in the emission current Ie is monitored by the emission current monitoring controller 58, and when an increase in the emission current of 3% is detected, a power supply 51 for applying an element voltage to the electron emission element is used. And the peak value of the voltage is 15V
A command was issued to replace and apply one pulse having a peak value of the drive voltage Vf of 14 V and drive (characteristic recovery drive). The pulse width of the peak value of 15 V was set to 0.08 msec, which is 40% of 0.2 msec.

The device current If and the emission current Ie for the device C were both measured when a peak value of 14 V was applied.

When the driving experiment was performed over the above-mentioned 500 hours, in the element C, the emission current fluctuated only by about 3% within the above-mentioned driving control range, and the device C was able to be driven extremely stably. Note that the element C has a characteristic that the element current If increases when the peak value is 14 V,
This is considered to be due to reasons such as incomplete removal of organic substances.

That is, according to the driving method of the present embodiment,
Due to the incomplete removal of organic substances, etc., the device current If increases, and the emission current Ie increases accordingly. It is.

Example 3 In Example 3, an image forming apparatus as shown in FIG. 9 was prepared using an electron source (FIG. 8) in which a plurality of the electron-emitting devices shown in FIG. 20 were arranged. An example in which the driving method of the present embodiment is applied will be described.

FIG. 16 is a plan view of a part of a substrate 71 on which a plurality of electron-emitting devices 74 are arranged in a matrix. The electron source of the image forming apparatus according to the third embodiment includes a plurality of the electron-emitting devices illustrated in FIG. 20 arranged in a matrix.

FIG. 17 is a sectional view taken along the line AA ′ of FIG. However, the same numbers in both figures represent the same ones. Here, 1 is a substrate, and 72 is Dox in FIG.
Part of the x-direction wiring (lower wiring) corresponding to m, 73 is shown in FIG.
Of the y-direction wiring (upper wiring) corresponding to Doyn, 4 is a conductive film, 2 and 3 are electrodes, 131 is an interlayer insulating layer, 132
Is a contact hole for electrical connection between the electrode 3 and the lower wiring 72.

Next, this manufacturing method will be specifically described in the order of steps with reference to FIGS. (Step-a) 0.5 μm thick on clean blue sheet glass
A photoresist (RD-2000N: manufactured by Hitachi Chemical Co., Ltd.) is spin-coated and baked on a substrate 1 on which a silicon oxide film is formed by sputtering, and then a photomask image is exposed and developed to form a resist pattern of the lower wiring 72. To form After that, Cr having a thickness of 20 nm, Cu having a thickness of 600 nm, and Cr having a thickness of 50 nm are sequentially laminated by vacuum evaporation,
Lower wiring 72 made of Cr / Cu / Cr by lift-off
Is formed (FIG. 18A). (Step-b) Next, an interlayer insulating layer 131 made of a silicon oxide film having a thickness of 1.0 μm is deposited by RF sputtering (FIG. 18B). (Step-c) A photoresist pattern for forming the contact hole 132 is formed in the silicon oxide film deposited in the step b, and the interlayer insulating layer 131 is etched using the photoresist pattern as a mask to form the contact hole 132. Etching is performed using RIE (Reactive Ion Et) using CF4 and H2 gas.
ching) method (FIG. 18 (c)). (Step-d) Thereafter, a pattern in which the gap between the electrodes 2 and 3 and the electrodes 2 and 3 is to be L is formed by photoresist (RD-RD).
2000N manufactured by Hitachi Chemical Co., Ltd.), and 5 nm thick Ti and 50 nm thick Pt were sequentially deposited by a vacuum evaporation method. Dissolve this photoresist pattern with an organic solvent,
The Pt / Ti deposited film is lifted off, and the electrode interval L is 10 μm.
m, and electrodes 2 and 3 having an electrode width W1 of 200 μm.
Was formed (FIG. 18D). (Step-e) Ti having a thickness of 5 nm and Au having a thickness of 1 μm are sequentially deposited by vacuum evaporation to form a photoresist pattern of the upper wiring 73, and then Au is formed by wet etching.
Then, unnecessary portions of Ti were removed by dry etching to form an upper wiring 73 made of Au / Ti (FIG. 19E). (Step-f) Conductive film 4 of electron-emitting device involved in this step
Is a mask having an interelectrode gap L and an opening in the vicinity thereof, and a Cr film 133 having a thickness of 100 nm is deposited and patterned by vacuum deposition using this mask.
Further, organic Pd (ccp-4230 manufactured by Okuno Pharmaceutical Co., Ltd.) was spin-coated with a spinner and baked at 300 ° C. for 10 minutes (FIG. 19F). The conductive film 4 made of Pd as a main element thus formed has a thickness of 10 n.
m, and the sheet resistance value was 5 × 10 4 Ω / □. (Step-g) The Cr film 133 and the baked conductive film 4 were etched with an acid etchant to form a desired pattern (FIG. 19 (g)). (Step-h) A resist was applied to the entire surface, developed after exposure using a mask, and the resist was removed only in the contact hole 132 portion. After that, by vacuum evaporation, a thickness of 5 n
The contact hole 132 was buried by sequentially depositing Ti of m and Au of 1 μm in thickness by vacuum evaporation, and removing unnecessary portions by lift-off (FIG. 19).
(H)).

According to the above steps, a plurality of conductive films are formed on the insulating substrate 1 by simple matrix wiring with the lower wiring 72 and the upper wiring 73, and the electron source substrate 71 before forming is formed.
Was formed.

Subsequently, an image forming apparatus (flat panel display) was prepared using the above-mentioned electron source. This creation procedure will be described below with reference to FIGS. (Step-i) The face plate 86 was prepared as follows. On the cleaned glass substrate 83, a tin oxide-indium oxide (ITO) thin film is formed by a sputtering method (not shown), and a fluorescent film 8 is formed thereon by a printing method.
4 was created. As will be described later, the ITO thin film is for applying a potential to extract electrons emitted from the electron-emitting device. The fluorescent film 84 was a fluorescent film shown in FIG. 10A in which stripe-shaped phosphors (R, G, B) 92 and black conductive materials (black stripes) 91 were alternately arranged. Further, after the phosphor film 84 is formed, a smoothing process (usually called filming) of the inner surface of the phosphor film 84 is performed, and a metal back 85 made of an Al thin film is formed on the phosphor film 84 by a sputtering method. 5
The film was formed to have a thickness of 0 nm. Through the above steps, the face plate 86 was prepared. (Step-j) After fixing the electron source substrate 71 on which a large number of electron-emitting devices before forming are formed to form a rear plate 81, a face plate 86 is supported by a supporting frame 82 about 5 mm above the electron source substrate 71. Then, frit glass was applied to the joint between the face plate 86, the support frame 82, and the rear plate 81, and was baked at 400 ° C. in the air for 10 minutes to seal the glass. In performing the sealing, sufficient alignment between the phosphors of each color and the electron-emitting devices was performed in order to correctly reproduce color display.

Next, a process performed on the electron-emitting device in the envelope will be described. (Step-k) The envelope 88 completed as described above is
Connected to a vacuum exhaust device as shown in FIG.
The atmosphere in 8 was exhausted by a vacuum pump through an exhaust pipe 132.

In FIG. 11, the display panel 101 is connected to a vacuum chamber 133 via an exhaust pipe 132.
An exhaust device 135 is connected to the vacuum chamber 133, and a gate valve 134 is provided therebetween. Further, a pressure gauge 136 is provided in the vacuum chamber 133.
A quadrupole mass spectrometer (Q-MS) 137 is attached, and the internal pressure and each partial pressure of the residual gas can be monitored. Since it is difficult to directly measure the pressure in the envelope 88, the pressure in the vacuum chamber 133 and the gas partial pressure are regarded as the pressure (or gas partial pressure) in the envelope for convenience. The exhaust device 135 is an ultra-high vacuum exhaust device including a sorption pump and an ion pump. A plurality of gas introduction devices are connected to the vacuum chamber 133. In the figure, a cylinder or an ampule for introducing the introduction material source 140, a gas introduction control device (such as a solenoid valve) 139, and one gas introduction line 138 are provided. Although only the drawing is illustrated, a plurality of gas introduction paths are actually secured, and several kinds of gases can be introduced into the envelope. As the gas introduction control unit 139, an electromagnetic valve, a needle valve, a mass flow controller, a slow leak valve, or the like is used according to the type of the substance to be introduced, the flow rate, the required control accuracy, and the like.

In this manner, the envelope 88 is connected to the exhaust device 13.
After exhausting at 5 and reaching a sufficient degree of vacuum, the outer terminal D
Electron emission device 74 through xo1 to Doxm and Doy1 to Doyn
A voltage was applied between the electrodes 2 and 3 to flow a current through each conductive film 4. By this step, a gap 6 was formed in a part of each conductive film 4 (forming processing was performed). The voltage waveform of the forming process was a rectangular wave pulse as shown in FIG. 4B, and the peak value was gradually increased. In this embodiment, T
1 was set to 1 ms, T2 was set to 10 ms, and the resistance of the selected wiring was measured by inserting a rectangular wave pulse having a peak value of 0.1 V between triangular wave pulses and measuring the current. When the resistance value exceeded 1 MΩ per element, the forming processing of the selected line was terminated, and the same processing was performed on the next wiring. With such a procedure, the forming process was performed on all the wirings (that is, the electron-emitting devices). (Step-1) Next, acetone was introduced from the introduced substance source 140 through the slow leak valve into the envelope, and 1.3 ×
10 minus 3 [Pa] was maintained. As in the first embodiment, the pulse waveform was a rectangular wave, and a pulse having a peak value of 15 V was applied to the selected line. In the third embodiment, the device current If
The activation treatment was performed while measuring. As described above, the forming and the activation treatments were performed, and an electron source substrate was formed. (Step-m) Subsequently, a stabilization treatment was performed. The stabilization process was performed by evacuating the entire envelope 88 while heating it at about 200 ° C. for 2 hours. (Step-n) Next, the exhaust pipe was welded by heating with a gas burner, and the envelope was sealed.

Finally, in order to further maintain the degree of vacuum after sealing, the Ba getter provided outside the image display area on the face plate 86 side was evaporated by a high frequency heating method.

In the image display device of the present embodiment completed as described above, the signal generating means (not shown) supplies
Electrons were emitted by applying a scanning signal to each electron-emitting device through x1 to Dxm and applying a modulation signal to each electron-emitting device through Dy1 to Dyn.

At the same time, a high voltage of several KV or more is applied to the metal back 85 or the transparent electrode (ITO) through the high voltage terminal Hv, and the emitted electrons are accelerated to collide with the fluorescent film 84 to excite and emit light. The image was displayed.

Next, the driving method of the third embodiment was performed.

First, by setting the peak value of the voltage pulse applied to each electron-emitting device to 15 V, each line of the electron-emitting device group connected to the external terminals Dx1 to Dxm is driven so that all the devices are sequentially driven. They were sequentially driven, and the maximum value of the emission current at that time was measured. Then, the peak value was set to 14 V, and the maximum value of the emission current was measured in the same manner as described above (first measurement step).
However, each line was about 40% at 15 V. Therefore, when a pulse having a peak value of 15 V is applied, if the pulse width is about 40% as compared with the case of a pulse voltage of 14 V, it is confirmed that the charges captured by the anode electrode per unit time are almost equal. Was done. Then, 300
Time characteristics were evaluated.

In this case, a rectangular waveform was used as the pulse waveform, and the peak value of the driving voltage Vf was basically kept constant at 14 V, and gradation display was performed by changing the pulse width. The rise of the emission current Ie is monitored by the emission current monitoring controller 58. When an increase in the emission current of 3% or more is detected at the maximum, one pulse having a peak value of 15V is generated by the drive voltage V
The peak value of f was applied to each element in place of a 14 V pulse (characteristic recovery drive). The pulse width of the peak value of 15V is 40% of that when the pulse of 14V is applied. For this reason, the characteristic recovery drive can be performed without causing a luminance variation or the like in the displayed image. The emission current Ie was measured when a peak value of 14 V was applied.

As a result of the above-mentioned characteristic evaluation for 300 hours, a change in emission current with time was small, and a good image was displayed.

Example 4 In Example 4, a flat panel display was manufactured. The display panel 101 constituting the flat panel display of this embodiment was created in the same manner as in the above-described third embodiment (step-a to step-n) (FIG. 9).

The driving method according to the fourth embodiment will be described below. FIG. 23 shows a drive circuit according to the fourth embodiment. In this figure, the same parts as those of the basic drive circuit shown in FIG. 13 are given the same numbers.

In the figure, reference numeral 101 denotes the above-mentioned display panel, which is connected to an external electric circuit via terminals Dox1 to Doxm and Doy1 to Doyn. The high voltage terminal Hv on the face plate is also connected to an external high voltage power supply Va. The terminals Dox1 to Doxm are used to sequentially drive the electron-emitting devices provided in the panel, that is, the electron-emitting devices arranged in a matrix of m rows and n columns, one row at a time. A scanning signal is applied. On the other hand, to the terminals Doy1 to Doyn, a modulation signal for controlling the output electron beam of each of the electron-emitting devices in one row selected by the scanning signal is applied.

Next, the scanning circuit 102 will be described.
This circuit includes m switching elements inside, and each switching element selects either the output voltage of the DC voltage source Vx or 0 [V] (ground level), and the terminal of the display panel 101. It is electrically connected to Dox1 to Doxm. Each switching element operates based on the control signal Tscan output from the control circuit 103. However, in practice, it can be easily configured by combining switching elements such as FETs.

In the case of the fourth embodiment, the DC voltage source Vx has the characteristics of the surface conduction electron-emitting device illustrated in FIG. 6 (the electron emission threshold voltage Vth was actually 8 [V]). ), A constant voltage of 7 [V] is set to be output so that the driving voltage applied to the unscanned element is equal to or lower than the electron emission threshold voltage.

Next, the flow of the input image signal will be described.

The input composite image signal is converted by a decoder 110 into a luminance signal of three primary colors and a horizontal and vertical synchronizing signal (for the sake of explanation, the synchronizing signal Tsync
). Also, the control circuit 103
Has a function of coordinating the operation of each part so that an appropriate display is performed based on an image signal input from the outside. Based on this synchronization signal Tsync, Tad, Tps, Tscan and Tsft and Tmry and Tmo
The control signals d, Tv ', Tv, and Tmes are generated.

On the other hand, the luminance signals of the three primary colors are input to an ADC (analog-digital converter) 111 and are converted into 8-bit digital signals at the timing of the sampling clock Tad. The number of bits at this time is determined according to the required number of gradations (the number of colors) of the image to be displayed. In the fourth embodiment, the number of bits is 8 in order to realize 256 gradations of each RGB color (about 16.7 million colors). Bit decided. The digital luminance signal thus converted is input to a P / S (parallel / serial) conversion circuit 112 because it is converted in the order according to the pixel arrangement of the phosphor on the face plate. Serialized data (8
) Is input to the shift register 104 through the multiplication switching circuit 115. This multiplication switching circuit 11
5 will be described later.

The shift register 104 is for serially / parallel converting the digital signal input serially in time series for each line of an image, and is based on a control signal Tsft sent from the control circuit 103. (Ie, the control signal Tsft may be a shift clock of the shift register 104). The data of one line of the image subjected to the serial / parallel conversion (corresponding to the drive data of n electron-emitting devices) is output from the shift register 104 as n parallel signals Id1 to Idn.

The line memory 105 is a storage unit for storing data for one line of an image for a required time only, and stores the contents of Id1 to Idn as appropriate according to a control signal Tmry sent from the control circuit 103. These stored contents are output as Id'1 to Id'n and input to the pulse width modulation circuit 106.

The pulse width modulation circuit 107 is for generating a pulse having a time width corresponding to each of the image data Id'1 to Id'n, and the output is a terminal Id "1 to Id". Connected to the gate of the switch 108 through n.
Then, a voltage signal having a pulse width corresponding to the data is output in accordance with the timing signal Tmod from the control circuit 103. The internal configuration will be described with reference to FIG. 401
Numeral denotes a down counter, and n rows are arranged for the number of column wirings. Data input terminals are connected to data lines Id′1 to Id′n from the line memory 105, respectively. The data load terminal LD is commonly wired and connected to a signal Tmod from the control circuit 103. Thereby, the countdown data is loaded from Id'1 to Id'n in accordance with the timing of Tmod. The counter clock clk is also commonly wired, and is connected to the clock output Pclk of the internal countdown clock generation circuit 402. Also,
The clock of the clock generation circuit 402 is generated by being reset by Tmod. The frequency of Pclk must be equal to or more than the count of the counter of the Tmod signal (256 in the fourth embodiment because of the 8-bit counter). However, in the fourth embodiment, each selection switching time is taken into consideration. And set it to 260 times. With these settings, the down counter 401
Is counted down by the counter clock Pclk at the same time as the data is loaded at the timing of the signal Tmod, and the clr signal becomes true (5 V) when the count value becomes "0". Since this signal switches the output of the voltage source by the gate terminal of the switch 108, a voltage is applied to the column wiring corresponding to this time, and pulse width modulation is realized.

Next, the voltage source 109 outputs a peak value for performing pulse width modulation. In the fourth embodiment, two types of voltage values can be switched and output according to a switching signal Tv from the control circuit 103 as described later.

The initial current memory 113 stores the emission current Ie in the initial state as described later, and the control circuit 103 reads and writes values of m rows.

The emission current measuring circuit 114 measures the emission current of each scanning line in accordance with the measurement timing Tmes output from the control circuit 103, and transmits the measured value as a digital value to the control circuit 103. .

FIG. 25 is a circuit diagram showing a configuration of emission current measuring circuit 114.

In the figure, reference numeral 2501 denotes a detection resistor,
It is arranged between a and the high voltage terminal Hv, and generates a potential difference according to the flowing current. Reference numeral 2502 denotes an isolation amplifier which amplifies a voltage generated between both ends of the detection resistor 2501 with an appropriate gain, and further supplies a high voltage directly to the A / D converter 2503.
And to insulate the control circuit 103 from conduction. The analog current value thus insulated from the high voltage is input to the A / D converter 2503, A / D converted according to the timing of Tmes, and the digital value is output to the control circuit 103.

The function of each component of the drive circuit has been described above. Next, a method of realizing the embodiment of the present invention will be described.

First, by setting the peak value of the voltage pulse applied to each electron-emitting device to 15 V, each line of the electron-emitting device group connected to the external terminals Dox1 to Doxm is driven so that all the devices are sequentially driven. They were sequentially driven, and the maximum value of the emission current at that time was measured.

This measurement can be performed using the driving circuit shown in FIG. That is, the voltage source 1
09 normally outputs -7V to each of the column wirings Doy1 to Doyn, but switches to -8V at the time of 15V measurement, so that the applied voltage to each element is changed to the normal 14V (drive voltage V
f) Can be raised more.

The actual voltage source 109 for realizing this is
26 is shown in FIG.

A buffer amplifier 2601 is connected to each column wiring. The buffer amplifier 2601 outputs the same voltage as the input voltage as it is. However, the buffer amplifier 2601 can output a current necessary to drive each element.
When 8 is switched to ground, it has a current limiting function so as not to heat. These buffer amplifiers are specifically composed of operational amplifiers and the like. The inputs of these buffer amplifiers are short-circuited to each column and connected to the voltage switch 2602.

The voltage switch 2602 is connected to the control circuit 103
Is controlled by the signal Tv. Normally, it is connected to a -7V power supply, but is connected to a -8V power supply when measuring 15V. Here, since the scanning circuit power supply Vx is set to 7 V as described above, the voltage applied to the element becomes 15 V. The control circuit 103 measures the emission current for each scan line at this time using the emission current measurement circuit 114 described above, and temporarily stores the emission current in the initial current memory 113.

Subsequently, the peak value was set to 14 V (in this case, the output voltage of the voltage source 109 was returned to -7 V), and the maximum value of the emission current was measured in the same manner as described above, and compared with the stored 15 V measurement value. However, each line was about 40% at 15 V. Thus, when a pulse having a peak value of 15 V is applied, the pulse height is about 40% higher than that of a case of 14 V.
It has been confirmed that the charge captured by the anode electrode per unit time becomes approximately equal when the pulse width is set to the above.

The measured value at 14 V was stored in the initial current memory 113 as the original emission current value (first measurement step).

As described above, in the fourth embodiment, the initial emission current value was measured using the actual drive circuit as it is. However, the measurement can be performed by providing a dedicated inspection device and writing the value to the memory of the drive circuit. Good.

Subsequently, an actual image display was performed.

The drive pulse waveform of the fourth embodiment uses a rectangular wave, and the peak value of the drive voltage Vf is basically fixed at 14 V, and gradation display is performed by changing the pulse width (pulse width modulation). .

FIG. 27 shows the operation at the time of actual display driving.
A description will be given based on the flowchart shown in FIG.

When the driving is started, first, a time waiting loop is started until the emission current measurement time comes (S1). Then, when the measurement time comes, the emission currents Ie1 to Iem for each scanning line are measured (S2: second measurement step). After this measurement is completed, the counter k of the current comparison loop is reset to “1” (S3), and the emission current value I of each line is reset.
ek is compared with the initial emission current Iedk stored in the initial current memory 113. In the fourth embodiment, the dispersion of the measurement,
In order to prevent driving by an excessively high voltage Vf, a comparison was made with a value obtained by increasing the initial emission current Iedk by 3% (S4). If the emission current Iek is larger than the value obtained by increasing Iedk by 3%, the process proceeds to step S5, and the k-th line voltage switching flag is turned on. In step S4, the emission current Iek is smaller than the value obtained by increasing 3% of Iedk, or after executing step S5, the process proceeds to step S6, in which the value of the counter k is incremented. If it exceeds m, it is determined that the current comparison has been completed and the process proceeds to step S8. If the count k does not exceed “m”, the process proceeds to step S7 to continue the comparison.

When the comparison is completed, in step S8, driving is performed according to the voltage switching flag at the time of driving the next frame (characteristic recovery driving). More specifically, the control circuit 1
03, a voltage switching flag is checked for each drive scanning line, and when the flag is on, the multiplication switching circuit 115 is switched by the Tv 'signal to switch the P / S conversion circuit 11;
A value obtained by multiplying the data from 2 by “0.4” is output to the shift register 104. That is, the multiplication switching circuit 115
Outputs the data from the P / S conversion circuit 112 as it is during normal driving, but outputs "0.4" times only when the Tv 'signal comes. At the same time, the control circuit 103 switches the voltage of the voltage source 109 to “−8 V” according to the Tv signal. Even when driving is performed by raising the driving voltage by these operations, the characteristic recovery driving can be performed without disturbing the desired gradation by reducing the pulse width.

In this way, the process proceeds to step S9, where the driving according to the voltage switching flag is performed only for one frame, the flag is reset, and if the driving is not completed in step S10, the operation returns to the normal driving, and the measurement wait loop is started. Return.

With the above-described driving, a high-quality image with very little change in luminance and very little deterioration in long-time driving can be realized.

As described above, according to the present embodiment, fluctuations in device characteristics in which emission current and device current increase during long-time driving due to incomplete removal of organic substances and the like. It is possible to effectively suppress the emission current and stabilize the emission current and the device current for a long time.

At the same time, since a voltage V2 higher than the drive voltage Vf is applied as necessary, deterioration of element characteristics can be suppressed as much as possible.

[0270]

As described above, according to the present invention, there is an effect that deterioration of the electron emission characteristics of the electron-emitting device can be prevented.

Further, according to the present invention, there is an effect that fluctuations in device current or emission current characteristics with respect to a predetermined applied voltage to the electron emission device are suppressed, and stable electron emission characteristics can be maintained for a long period of time.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic diagrams illustrating an example of a configuration of an electron-emitting device according to an embodiment of the present invention, wherein FIG. 1A is a top view and FIG.

FIG. 2 is a schematic diagram showing another example of the configuration of the electron-emitting device according to the present embodiment.

FIG. 3 is a diagram illustrating an example of a method for manufacturing the electron-emitting device according to the embodiment.

FIG. 4 is a diagram showing an example of a voltage waveform in an energization forming process that can be employed in manufacturing the electron-emitting device of the present embodiment.

FIG. 5 is a block diagram illustrating an example of a vacuum processing apparatus having a measurement evaluation function according to the present embodiment.

FIG. 6 is a graph showing an example of the relationship between the emission current Ie, the device current If, and the device voltage Vf in the electron-emitting device of the present embodiment.

FIG. 7 is a flowchart showing a process in an element current controller according to the present embodiment.

FIG. 8 is a plan view showing an example of an electron source in which electron-emitting devices are arranged in a matrix.

FIG. 9 is an external perspective view showing the display panel according to the present embodiment in a partially broken manner.

FIG. 10 is a schematic diagram showing an example of the arrangement of phosphors of a phosphor film according to the present embodiment.

FIG. 11 is a diagram showing a configuration of a vacuum evacuation apparatus for performing a forming and activating step of the display panel according to the present embodiment.

FIG. 12 shows forming of a display panel of this embodiment mode;
It is a figure showing the connection method for an activation process.

FIG. 13 is a block diagram illustrating an example of a drive circuit of a display panel in the image display device of the present embodiment.

FIG. 14 is a diagram illustrating an example of an electron source having a ladder arrangement according to the present embodiment.

15 is an external perspective view showing an example of a display panel using the electron source shown in FIG. 14 with a part thereof cut away.

FIG. 16 is a partial plan view of an electron source having a simple matrix arrangement according to the present embodiment.

FIG. 17 is a sectional view taken along line A-A ′ of FIG. 16;

18 is a cross-sectional view for explaining a manufacturing process of the electron source shown in FIG.

19 is a cross-sectional view for explaining a manufacturing process of the electron source shown in FIG.

FIG. 20 is a schematic view showing an example of an electron-emitting device having a carbon film formed thereon.

FIG. 21 is a schematic view illustrating a manufacturing process of an electron-emitting device having a carbon film formed thereon.

FIG. 22 is a diagram showing an example of a pulse-like voltage waveform preferably applied to an element in an activation step.

FIG. 23 is a block diagram illustrating an example of a drive circuit of the image forming apparatus according to the present embodiment.

FIG. 24 is a block diagram illustrating an example of a pulse width modulation circuit according to the present embodiment.

FIG. 25 is a block diagram showing an example of a circuit for measuring an emission current according to the present embodiment.

FIG. 26 is a block diagram illustrating an example of a configuration of a voltage source.

FIG. 27 is a flowchart illustrating an example of a display driving method according to the present embodiment.

Claims (10)

[Claims] A first measuring step of measuring an emission current Ie1 emitted from the electron-emitting device and / or a device current If1 flowing through the electron-emitting device when a voltage V1 is applied to the electron-emitting device; After the first measurement step, a second measurement of the emission current Ie2 emitted from the electron-emitting device when the voltage V1 is applied to the electron-emitting device and / or the device current If2 flowing through the electron-emitting device is performed. A measuring step, and a voltage applying step of applying a voltage V2 larger than the voltage V1 to the electron-emitting device when the emission current Ie2 is larger than Ie1 and / or when the device current If2 is larger than If1. And a method for driving an electron-emitting device. 2. The electron emission device according to claim 1, wherein after the voltage application step is performed, the first measurement step, the second measurement step, and the voltage application step are further repeated. Drive method. 3. The voltage V2 is a maximum voltage value V applied to the electron-emitting device before the first measuring step.
2. The method of driving an electron-emitting device according to claim 1, wherein the value is not more than max. 4. The method according to claim 1, wherein a voltage applied to the electron-emitting device is a pulsed voltage. 5. A first measuring step of measuring an emission current Ie1 emitted from the electron-emitting device and / or a device current If1 flowing through the electron-emitting device when a pulsed voltage is applied to the electron-emitting device. After the first measurement step, when the same waveform as the pulsed voltage waveform is applied to the electron-emitting device, the emission current Ie2 emitted from the electron-emitting device, and / or the electron-emitting device A second measuring step of measuring a flowing device current If2, and the first measurement for the electron-emitting device when the emission current Ie2 is larger than Ie1 and / or when the device current If2 is larger than If1. A voltage application step of applying a pulsed voltage having a power greater than the power of the pulse applied in the step. 6. The method according to claim 5, wherein the maximum voltage value in the pulse applied in the voltage applying step is larger than the maximum voltage value in the pulse applied in the first measuring step. A method for driving the electron-emitting device. 7. The electron emission device according to claim 5, wherein, after performing the voltage applying step, the first measuring step, the second measuring step, and the voltage applying step are further repeated. Drive method. 8. The method according to claim 5, wherein a power of a pulse applied in the voltage applying step is equal to or less than a maximum power applied to the electron-emitting device before the first measuring step. 3. The method for driving an electron-emitting device according to claim 1. 9. A method for driving an electron source in which a plurality of electron-emitting devices are arranged, wherein the electron-emitting devices are driven by the method according to claim 5. Description: How to drive the electron source. 10. A method for driving an image forming apparatus having an electron source and an image forming member, wherein the electron source is driven by the method according to claim 9. Method.